Hi Rob, On Tue, 26 Sept 2023 at 11:29, Rob Herring <robh@xxxxxxxxxx> wrote: > > On Tue, Sep 26, 2023 at 2:48 AM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote: > > > > Hello, > > > > > > > > > These are firmware bindings, as indicated, but I > > > > > > > took them out of the /firmware node since that is for a different > > > > > > > purpose. Rob suggested that partitions was a good place. We have fwupd > > > > > > > using DT to hold the firmware-update information, so I expect it will > > > > > > > move to use these bindings too. > > > > > > > > > > > > I would definitely use fixed partitions as that's what you need then: > > > > > > registering where everything starts and ends. If you have "in-band" > > > > > > meta data you might require a compatible, but I don't think you > > > > > > do, in this case you should probably carry the content through a label > > > > > > (which will become the partition name) and we can discuss additional > > > > > > properties if needed. > > > > > > > > > > I believe I am going to need a compatible string at the 'partitions' > > > > > level to indicate that this is the binman scheme. But we can leave > > > > > that until later. > > > > > > > > Perhaps: > > > > > > > > compatible = "binman", "fixed-partitions"; > > > > > > > > Though I don't understand why binman couldn't just understand what > > > > "fixed-partitions" means rather than "binman". > > > > > > Well so long as we don't add any binman things in here, you are right. > > > > > > But the eventual goal is parity with current Binman functionality, > > > which writes the entire (augmented) description to the DT, allowing > > > tools to rebuild / repack / replace pieces later, maintaining the same > > > alignment constraints, etc. I am assuming that properties like 'align > > > = <16>' would not fit with fixed-partitions. > > > > I am personally not bothered by this kind of properties. But if we plan > > on adding too much properties, I will advise to indeed use another name > > than fixed-partitions (or add the "binman" secondary compatible) > > otherwise it's gonna be hard to support in the code while still > > restraining as much as we can the other partition schema. > > Agreed. It's a trade off. I think we need enough to understand the > problem (not just presented with a solution), agree on the general > solution/direction, and then discuss specific additions. > > > > But if we don't preserve > > > these properties then Binman cannot do repacking reliably. Perhaps for > > > now I could put the augmented DT in its own section somewhere, but I > > > am just not sure if that will work in a real system. E.g. with VBE the > > > goal is to use the DT to figure out how to access the firmware, update > > > it, etc. > > VBE? > > > > Is it not possible to have my own node with whatever things Binman > > > needs in it (subject to review of course)? i.e. could we discuss how > > > to encode it, but argue less about whether things are needed? I > > > kind-of feel I know what is needed, since I wrote the tool. > > What we don't need is the same information in 2 places for the DTB > used at runtime. If the binman node is removed, do whatever you want. > If you want to keep it at runtime, then it's got to extend what we > already have. > > I don't think anyone is disagreeing about whether specific information > is needed or not. > > > > > > So you are suggesting 'label' for the contents. Rob suggested > > > > > 'compatible' [1], so what should I do? > > > > > > > > "label" is for consumption by humans, not tools/software. Compatible > > > > values are documented, label values are not. Though the partition > > > > stuff started out using label long ago and it's evolved to preferring > > > > compatible. > > > > > > OK so we are agreed that we are going with 'compatible'. > > > > Still strongly disagree here. > > Miquel is right. I was confused here. "label" is still pretty much > used for what the image is. Though we do have "u-boot,env" for both it > seems. > > My position on "label" stands. To the extent we have images for common > components, I think we should standardize the names. Certainly if > tools rely on the names, then they should be documented. OK thanks for clearing that up. But at present 'label' is free-form text. If I change it to an enum, won't that break things? If not, how do I actually do it? There is a u-boot.yaml but it doesn't actually have a "u-boot" label in the schema. In fact it seems that the label is not validated at all? > > > > My understanding is that a compatible carries how the content is > > organized, and how this maybe specific (like you have in-band meta data > > data that needs to be parsed in a specific way or in your case > > additional specific properties in the DT which give more context about > > how the data is stored). But the real content of the partition, ie. if > > it contains a firmware, the kernel or some user data does not belong to > > the compatible. > > > > I.e: > > - The first byte of my partition gives the compression algorithm: > > -> compatible = "compressed-partition-foo"; > > or > > -> compatible = "fixed-partitions" + compression-algorithm = "foo"; > > - The partition contains a picture of my dog: > > -> label = "my dog is beautiful" > > but certainly not > > -> compatible = "my-dog"; > > IMO, compatible in this case should convey "JPEG image" or similar. > > > I don't see why, for the binman schema, we could not constrain the > > labels? > > Yes, but those should follow what we already have. "u-boot" for > example rather than "data,u-boot" which I think Simon had in some > version of this. Yes, don't worry, I had some feedback from Alper but have given up on that approach. Regards, Simon
